1 Field of the Invention
The invention relates to pile carpets comprising synthetic yarn or fibers, natural fibers, or blends thereof, and a heat-activated adhesive powder with a melting point substantially below that of the carpet fiber. In a process for production of carpet, adhesive powder may be applied and heat cured during the dyeing and finishing process steps causing the powder to completely melt and flow to points of intersecting fibers to create a bond upon subsequent cooling, thus altering the properties and performance of the finished carpet.
2. Description of Related Art
It has been known to blend non-adhesive fibers with potentially adhesive fibers to form a yarn or other textile structure, then to activate the potentially adhesive fibers to bond them to contacting fibers, thus modifying end-use properties of the yarn. U.S. Pat. No. 2,252,999 to Wallach, issued Aug. 19, 1941, provides a process wherein a yarn comprising an admixture of non-adhesive and potentially adhesive fiber is formed, the potentially adhesive fiber is activated, and the fibers compacted while in an adhesive condition so that they adhere to each other at points of contact. U.S. Pat. No. 3,877,214 to Van der Werf, issued Apr. 15, 1975, discloses a twist-free yarn comprising a polyamide fiber melting under a relatively low temperature as a bonding component. U.S. Pat. No. 3,494,819 to McAlister, issued Feb. 10, 1970 discloses a blend of fusible and non-fusible polyethylene terephthalate fibers incorporated into fabric, wherein the finished fabric is heated to fusion temperatures to provide improved pill resistance. U.S. Pat. No. 3,978,267 to Selwood, issued Aug. 31, 1976 discloses a substantially twistless compact yarn comprising a proportion of potentially adhesive fiber which have been activated to bond to contacting fibers.
The use of thermoplastic binder fibers in combination with structural fibers to form self-bonding nonwoven fabrics is known. U.S. Pat. No. 2,880,112 to Drelich, issued Mar. 31, 1959 discloses the use of nylon-6 to bond viscose rayon and other cellulosic materials to form washable nonwoven fabrics.
U.S. Pat. application Ser. No. 934,389 relates to a synthetic yarn blend for the carpeting, comprising a blend of nonadhesive fibers with heat-activated adhesive fibers with a melting point substantially below that of the nonadhesive fibers. In a process for production of carpet, exposure of the yarn to usual process conditions for twist setting the yarn causes the heat-activated adhesive fiber to melt substantially completely, losing its identity as a fiber, and to flow to points of intersecting fibers to create a bond upon cooling.
Cut-pile carpet is customarily produced from staple yarns or bulked continuous filament yarn. For example, staple fiber is conventionally carded, pinned, and spun or wrap spun into a singles yarn, which typically is twisted and plyed with similar yarn to form a 2-ply or 3-ply yarn construction. This yarn is twist set by utilizing one of several commercially available twist setting processes. In a typical process the yarn is passed through a heated chamber, while in a relaxed condition. The temperature of this process step is crucial to the proper twist setting of the base fiber, to obtain desired properties of the final carpet product. For nylon-6 base fiber, the conditions for this step are typically 195-200.degree. C. with a residence time of about 60 seconds for the Suessen process and about 135-140 .degree. C. with a residence time of about 60 seconds for the Superba process.
Similarly, bulked continuous filament nylon yarn is produced according to various conventional methods. Twisting, entangling, or direct cabling may be utilized in various processes. For example, a 2-ply twisted yarn combining 2 ends of 1185 denier 70 filament yarn is prepared and subjected to conventional twist setting conditions, such as that for the staple yarn above or in an autoclave at 132.degree. C. in saturated steam, with a residence time of about 60 seconds.
Multiple ends of the twist set yarns are incorporated into a fabric backing to produce a pile surface, for example by tufting, weaving, or fusion bonding, and conventionally finished to obtain the desired carpet product.